Knowledge before Cassini-Huygens

Hyperion
is one of Saturn's smaller satellites and its elliptical orbit lies between
that of Titan and Iapetus. Hyperion's low density indicates that the satellite
is mainly composed of water-ice with a small amount of rocky material. The
surface is covered with a darker material causing Hyperion to have a lower
albedo compared to other icy moons.

Hyperion's shape is very irregular
and it has been suggested that the satellite once was part of a larger object
that was fractured by an impact in the distant past. Hyperion's surface also
shows signs of heavy cratering with the largest crater approximately 120
km in diameter.

The orientation of Hyperion's axis of rotation is
chaotic and unpredictable. The cause for the chaotic rotation could be due
to the proximity of the large moon Titan, the ellipticity of Hyperions orbit
and the 3:4 resonance between the orbital period of Titan and Hyperion.